This application claims priority under 35 U.S.C. xc2xa7xc2xa7119 and/or 365 to Appln. No. 100 33 691.4 filed in Germany on Jul. 11, 2000, the entire content of which is hereby incorporated by reference.
The invention relates to a condenser neck provided between a steam turbine and a condenser located downstream from the steam turbine.
EP-A1-384 200 discloses an arrangement of a steam turbine and subsequent steam condenser. A coupling pipe and a condenser neck are located between the two elements that are located in one plane. The steam from the steam turbine is fed via the coupling pipe and condenser neck to the pipe bundle of the condenser. This condenser neck essentially has the task of providing a homogeneous flow field and a clean steam-flushing of the subsequent bundles of the condenser. The condenser neck of this steam condenser widens in a cone shape from the coupling pipe to the condenser.
Another embodiment of such a condenser neck is known from U.S. Pat. No. 2,939,685.
Also known are condenser necks that are comprised of level plates. Since very high vacuum forces act on the condenser neck, it is reinforced on the inside with pipes. Now and then, additional ribs are provided on the outside. These pipes are necessary, but significantly interfere with the flow of the steam. On the side of the pipes that faces away from the flow, oscillating vortices that are not very advantageous form and excite the support pipes and therefore the entire condenser neck. The result can be a failure of the reinforcement pipes, even a total failure of the system and damage of all involved components. During bypass operation, i.e., when hot steam is introduced directly into the condenser neck while bypassing the turbine, which occurs, for example, during a sudden shut-down of the turbine, there are overall difficulties in introducing the steam. There is a danger of erosion of the support pipes and walls. The large number of pipes used requires a complex assembly of the plates, pipes, and ribs with welding. Because it uses level plates, this type of condenser neck also has a shape with little advantages with respect to flow technology.
It is the objective of the invention to avoid the mentioned disadvantages. The invention solves the task of constructing a condenser neck with increased stability in relationship to external influences, whereby the flow of the steam is influenced or impaired as little as possible.
According to the invention, this is achieved by a condenser neck having two level cover plates and two side walls that widen in the flow direction of the steam and have a favorable shape with respect to flow technology.
This simple construction makes it possible that the forces acting on the condenser neck are absorbed in an improved manner. This is true in particular if the cover walls and/or side walls are reinforced with ribs. A pipe arranged between the cover walls is able to additionally support this reinforcement. The flow inside the condenser neck improves both because of the favorable shape as well as because previously known internal elements are eliminated. The existing pipe is preferably arranged so that it is located in a zone with little flow, so that the steam flow is influenced as little as possible. Any existing bypass lines may merge into the pipe as well as into the side and/or cover walls. If a compensator is provided between the turbine and the condenser, two connecting surfaces or connecting tabs are provided on the coupling pipe on the turbine side at the inlet opening; in this way the external loads are transmitted from the turbine side via a stabilized element onto the condenser casing. In an embodiment without compensator, the coupling pipe of the turbine is welded to the neck. The force in the condenser neck according to the invention is distributed evenly over its circumference.